Many machines, particularly earth working machines, use a hydrostatic drive system to drive the ground engaging traction devices of the machine. Such work machines when used in construction sites and off-road locations generally experience loss of traction. For example, slipping may occur to either the front or rear sets of the ground engaging traction devices on sloped terrain or loose soil.
Typically, the hydrostatic drive system includes an engine that provides rotational motion to a propel pump which produces highly pressurized fluid to first and second variable displacement motors that drive the ground engaging traction devices. When one of the ground engaging traction devices begin to slip, the motor that is associated with the slipping ground engaging traction device receives most of the hydraulic fluid flow from the pump. Consequently, little fluid flow is left for the other motor. Thus, the machine is prevented from moving during a slipping condition. Further, the slipping condition wastes engine horsepower and can damage the motors from over-speeding.
The present invention is directed toward overcoming one or more of the problems as set forth above.